Universally adjustable antenna



Jan. 8, 1952 Filed April 20, 1949 W. J. RACE UNIVERSALLY ADJUSTABLE ANTENNA 2 SHEETS- SHEET l INVENTOR.

Jan. 8, 1952 w. J. RACE UNIVERSALLY ADJUSTABLE ANTENNA Filed April 20, 1949 2 SHEETSSHEET 2 X i VIIIIIIIIIJIIIIAaAW & \\N w 4A INVEA ITOR. CfFace BY '5", I M

w w m F NW Iva/Iv N N M, J r z. 1/ 74 N z a 0 \ldv 7 7 II! a w E Patented Jan. 8, 1952 UNIVERSALLY ADJUSTABLE! ANTENNA William J. Race, Franklin Park, IlL, assignor to Motorola, Inc., Chicago, 111., a corporation of Illinois Application April .20, 1949, Serial No. 88,533 8 Giaims. (01. 250-33) This invention relates to antennas for the reception of television, frequency-modulated and other high frequency signals, and particularly to universally adjustabl dipole antennas.

The prior art has made available to the public dipole antennas which are adjustable as to the lengths of their arms, the angular positions of the arms, and the orientation of the antenna as a whole. While such features of adjustability are very useful, they have in the past entailed some sacrifice in the uality of reception. Imperfect electrical connections between relatively sliding or rotating parts, as well as capacitive leakage losses, have attenuated the signal strength to an undesirable extent. All these factors have tended to reduce the popularity of such antennas.

An object of the present invention is to provide an improved adjustable antenna for the reception of high-frequency signals in which good electrical connections between relatively movable conductive parts are insured, and in which the capacitive leakage is kept down to a negligible amount.

A further object is to provide a highly adaptable dipole antenna which can be plugged directly into a receiver or into a separate base, as desired.

A further object is to provide a simple, inexpensive, adjustabledip'ole antenna which is attractive in appearance and adaptable to many uses.

A feature of the invention is the provision of a unique hub assembly for supporting the two arms of the dipole antenna in any selected angular positions relative to the axis of the hub. Electrical connections from the arms to the receiver are established through fixed conductors in the hub rather than through wires which are likely to flex and change positions and thereby introduce disturbances as the arms are moved.

Another feature is the provision of a novel plug and jack combination, the plug being secured to the hub assembly and the jack being mounted in the receiver or other supporting body. The plug is specially designed to present negligible capacitance between the circuit paths extending through it. The plug and jack together afford a rotatable joint which enables the antenna to be oriented in any desired fashion.

Still another feature is the provision of improved wiper contacts between the telescoped rods or tubes of each antenna arm to establish electrical connections therebetween and also frictionally retain such arms against accidental displacement relative to each other. These wipers consist of polygonal sleeves disposed between adjacent ones of the telescoped rods.

The foregoing and other objects, features and advantages of the invention will be understood more thoroughly from a study of the following description taken in connection with the accompany drawings, wherein:

Fig. 1 is a perspective view of a television receiver, with an antenna embodying the invention plugged directly into the receiver;

Fig. 2 is a perspective View" showing the antenna mounted on a separate base;

Fig. 3 is an elevational view of the antenna, with the supporting body therefor being shown in section;

Fig. 4 is a longitudinal section through the hub assembly, showing its relation to adjoining parts of the antenna structure;

Fig. 5 is a longitudinal section through the upper end of a dipole arm when the same is in collapsed position;

Fig. 6 is a cross section on the line 6-6 of Fig. 5; and

Fig. 7 is a detail perspective view of a wiper.

The dipole antenna illustrated herein is supported by a plug which is receivable in a jack associated with a receiver. The jack may be provided on the receiver cabinet or in a separate base, as desired. The plug is secured to a stationary insulating member which is part of a hub assembly including two rotatable metallic hub members positioned on either side of the insulating member. The rotatable hub members are held against the stationary member by a spindle or stud, with a substantial amount of friction between the cooperating faces of the stationary and movable hub members. The arms of the dipole are respectively sup ported by the rotatable hub members. Each of these arms comprises a plurality of telescoped tubes or rods, the outermost one of which is secured to the rotatable hub member. These members are slidable relative to each other for varying the effective length of the arm to correspond with the wave length of the signal that is being intercepted. To afford good electrical connections between the adjacent members and an adequate amount of friction therebetween, wipers are interposed between the members. These wipers are formed out of resilient sheet metal stock and have polygonal configurations so that they will bind tightly against both membersv of each pair. The spindle in the hub assembly is electrically connected to one of the rotatable hub members and insulated from the other rotatable hub member. This other hub member is electrically connected to the outer sleeve of the plug by a coiled spring that extends through the stationary hub member. The inner contact rod of the plug is screwed into the spindle. Thus, the two conductive parts of the plug are electrically connected respectively to the two arms of the dipole through the hub assembly without the use of any flexible wires. The inner contact rod of the plug is cut down to a much smaller diameter than is the contact rod of the conventional plug, and a thick washer of high-quality dielectric material is interposed between the contact rod and the outer sleeve. Both of these factors greatly reduce the capacitance of the plug and thereby render it suitable for highfrequency work. The jack affords a pivotal mounting for the plug whereby the orientation of the entire antenna structure can readily be adjusted.

Referring now to the detailed disclosure in the drawing, the dipole antenna structure I8 is adapted to be mounted directly on the cabinet l2 of a receiver 14, Fig. 1 (a portable television receiver being shown in this view), oron a separate base 18 as shown in Fig. 2. In the latter case the antenna I8 is connected to the receiver through a line I8. The construction of the antenna and the provisions for orienting the same are identical in the two embodiments. As shown in Fig. 3, a jack 28 is mounted on the cabinet I2 Or other supporting base. This jack is of a standard type except that it has a much lower capacitance than the conventional jack, the reduction of capacitance being effected by the use of high-quality dielectric separators. A low-capacitance plug 22 on the antenna I8 is received in the jack 28 and is rotatable therein to facilitate orientation of the antenna H].

A hub assembly 24 is supported by the plug 22, and a pair of dipole arms 26 extends from the hub assembly 24. Each of these arms 28 has three telescoping sections consisting of an outer tube 28, an intermediate tube 38 and an inner rod 32. Each of the rods 32 terminates at its outer end in an insulating ball 34 of high-quality dielectric material which serves as a convenient handle for extending or collapsing the telescoped sections and for orienting the antenna.

The hub assembly 24, shown best in Figs. 3 and 4, comprises a central stationary insulating member 36 of high-quality dielectric material and two outer rotatable members 38 and 48 of metal which are disposed on either side of the stationary member 36. Axial cavities 42 and 43 in the hub members 38 and 40, respectively, communicate with an axial opening 44 which extends through the stationary hub member 36. A stud or spindle 46 extends through the axial opening 44 and serves to hold the three hub members 36, 38 and 48 together. The stud 46 has a head 58 disposed in the cavity 42, and this head 58 is spaced from the adjacent portion of the hub member 38 by an insulating washer 52. The other end of the stud 46 is threaded to receive a pair of nuts 54 and 55 disposed in the cavity 43. As the nut 54 is tightened on the stud 46, it exerts pressure through the fiat washer 58 and the spring washer 58 against a portion of the hub member 48. The nut 55 serves to lock the nut 54. The hub members are pivotally mounted on annular bosses 68 and 62 extending laterally from the stationary hub member 86. Each of the rotatable hub members 38 and 48 has face-to-face contact with the stationary hub members 36 over a relatively large 4 surface area. The nut 54 is tightened sufficiently so that a substantial amount of friction exists between these cooperating faces. The end cavities 42 and 43 in the hub assembly 24 are closed by friction buttons 64.

The outer tube 28 in each of the antenna arm assemblies 26 is secured by a stud 66, Fig. 4, to a rotatable hub member 38 or 48. Each stud 66 is force-fitted into the lower end of the antenna tube 28 and into a suitable opening in the hub member 38 or 48. Also, it will be noted in Fig. 4 that the lower ends of the antenna tubes 28 are driven for short distances into the openings in the hub members 38 and 46 which receive the lower ends of the studs 66, thereby affording additional rigidity.

The intermediate antenna tubes 38 are slidable within the outer antenna tubes 28. Interposed between each pair of tubes 28 and 38 is a resilient contact sleeve or wiper '18, Figs. 5, 6 and '7. This wiper consists of flat spring stock, such as phosphor bronze, formed into a polygonal shape. A longitudinal gap or slit in the wiper it permits a limited amount of flexing. As shown best in Fig. 6, the fiat inner faces of the wiper i8 frictionaliy grip the exterior of the antenna tube 38, and the outer corner portions of the wiper 18 frictionally engage the inner surface of the antenna tube 28. The wiper i8 performs two functions; namely it holds the antenna tube 38 in a tight frictional grip and it affords a good electrical connection between the antenna tubes 28 and 30. The lower end of each antenna tube 30 is expanded slightly, as indicated at 12, Fig. 4, and the upper end of each antenna tube 28 has an inturned lip 74, Fig. 5, thereby preventing the tubes 28 and 38 from becoming disengaged when the antenna arm 26 is extended.

In similar fashion, a polygonal wiper 18, Figs. 5 and 6, is interposed between the antenna tube 30 and the inner antenna rod 32 of each antenna arm 26. This wiper 16 has the same functions as the wiper 18; that is, it established a good electrical connection between the rod 32 and the tube 36, and it affords a frictional binding connection between these parts. The lower end of each rod 32 is expanded slightly as indicated at 18, Fig, i, and the upper end of each tube 36 has an inturned lip 80, Fig. 5, preventing disengagement or the rod 32 and the tube 38. The balls 34 are forced onto the upper ends of the rods 32.

The antenna arms 26 can be made in as many sections as desired to secure the necessary amount of extension thereof. The length of each arm, the angularity between the arms, and the orientation of the antenna as a whole are adjusted to secure the optimum reception of a desired signal. The electrical connections from the antenna arms 26 to the receiver are made through the plug 22 and the jack 28.

The plug 22 has an outer tube or sleeve 82 which is received in a vertically extending socket in the lower portion of the stationary insulating member 36. A horizontal hole 84, Fig. 4, extends from this vertical socket to the face of the member 36 which adjoins the rotatable hub member 38. Disposed in the hole 84 is a small coiled spring 86 which bears at its opposite ends against the hub member 38 and the tube 82. This spring 86 serves as a contact member to establish an electrical connection between the tube 82 and the hub member 38 for all angular positions of the latter. This electrical connection is con tinued through the hub member 38 and the stud a sent 66 mounted therein to the antenna arm 26 that is connected to this hubmember 38.

The plug 22 has an inner member or contact rod 88, the shank 90 of which extends throughv the tube 82. At the upper end of the shank 90 is an integral threaded portion 92 which is threaded into a tapped opening in "the spindle 48. In order to keep the capacitance between the contact rod 88 and the Outer tube '82 down to a negligible value at high frequ'enriies, the shank 9B is made very much smaller in diameter, relative to the inner diameter of thetube 82, than is done in the conventional telephone plug. Furthermore, a thick insulating washer 94 of highquality dielectric material is inter osed between the lower end of the tube 82 and the protruding lower portion of the contact rod '88. The lower end of the tube B2 is recessed slightly, asind-i cated at 86, Fig. 4, to receive the insulating washer 94. Substantially the entire "space between the contact rod 88 and the tube 82 is therefore occupied only by air so that the capacity between the rod and the tube is a minimum. Thus, the contact rod 88 is effectively insulated from the outer tube at high frequencies, and it is electrically connected to the rotatable hub member do through the medium of the spindle '46. The hub member lll, in turn, is electrically connected to the antenna arm 26 which is mounted on this hub member.

The jackzfl, Fig. 3, which receives the plug 22 has a contact spring Hlll formed to cooperate with the protruding lower portion of the contact rod 88. This spring I00 is insulated from contact with the outer tube 82 of the plug 22, and it is electrically connected to a terminal I02, to which one of the conductors in a two-fwire parallel [line H14 is soldered. The other conductor of this line I04 is soldered to a terminal 106 which is *electrically connected to a portion of the jack that cooperates with the tube 82 of the plug 22. The line I04 leads to the antenna input terminals of the receiver. The jack 20 has a threaded shank I68 which extends through a suitable opening in the cabinet l2 or other support member and is insulated from contact therewith by insulating washers H0. Flat washers III are positioned adjacent the washers Hll. A knurled nut H2 is threaded on the protruding upper end of the shank I08 for securing the jack to the supporting body l2. The jack 20 permits the plug 22 to be rotated therein for swinging the antenna structure about a vertical axis to vary the orientation of the antenna.

The disclosed antenna structure is simple, sturdy and economical and it affords three degrees of adjustment of the antenna, namely, length of the arms 26, angularity of the arms 26 and orientation of the antenna Ill. The antenna, when collapsed, occupies very little space and can be packed into the lid of a carrying case, for example. It can be mounted either on the receiver itself, as shown in Fig. 1, or on a separate base as shown in Fig. 2. In either event it presents a very attractive appearance.

The disclosed details of the antenna structure may be modified without departing from the principles of the invention as set forth hereinabove. It is intended, therefore, that all modifications coming Within the spirit of the invention shall be included within the scope of the appended claims.

I claim:

1. An adjustable dipole antenna comprising a stationary insulating member, a pair of rotatablemetallic hub members respectively disposed on opposite sides or said insulating member, a spindle supported by said insulating memher and extending at opposite ends thereof into said hub members, said hub members being rotatable about said spindle asan axis, means elec trically connecting said spindle to one of said hub members, means insulating said spindle from the other of said hub members, a stationary spring contact member supported by said insulating member and engaging said other hub member, a pair of extensible antenna arms respectively connected to said hub members, each of said arms comprising telescoped metallic members slidable relative to eachother'a-nd spring contact means interposed between said members, and rigid electrical conductors secured to said stationary insulating member and respectively connected' electrically to said spring contact member and to said spindle.

2. An adjustable dipole antenna comprising a stationary insulating member, a pair of rotatable metallic hub members respectively disposed on opposite sides of said insulating member, aspindle supported by said insulating member and extending at opposite ends thereof into said hub members, a .pair of antenna arms respectively secured to said rotatable hub members, said hub members being rotatable about said spindle as an axis, means electrically connecting said spindle to one of said hub members, means insulating said spindle from the other of said hub members, a contact supported by said stationary insulating member engaging said other hub member, and electrical conductors insulated from each other and leading respectively from said spindle and said contact.

3. An adjustable dipole antenna comprising a pair or arms, a pair or" metallic hub members rotatable about a common axis and connected respectively to said arms, a stationary insulating member interposed between said hub members and having bosses on opposite sides thereof for supporting said hub members, a stud passing through said insulating member and having opposite ends thereof disposed respectively within said hub members, a nut threaded on said stud to draw said hub members into tight frictional cooperation with said stationary member, said spindle being electrically connected to one of said hub members and insulated from the other of said hub members, contact means supported by said stationary member cooperating with said other hub member, and electrical conductors insulated from each other and leading respectively from said spindle and from said contact means.

4. A universally adjustable dipole antenna adapted to be plugged into a jack or the like associated with a receiver, such antenna comprising a pair or extensible arms, a pair of rotatable metallic hub members respectively supporting said arms, a stationary insulating member interposed between said rotatable hub members, a spindle joining said rotatable hub members to said stationary insulating member, said spindle being electrically connected through one of said rotatable hub members to the antenna arm supported thereby and being insulated from the other of said hub members, a plug secured to said stationary member and receivable in said jack, said plug comprising an outer tubular member insulated from said spindle and an inner contact rod secured to said spindle, and spring contact means supported by said stationary member for electrically interconnecting said tubular plug member with said other hub member.

5. A high frequency antenna of the dipole type including a pair of adjustable arms and supporting means therefor, each of said arms including an elongated conducting tube secured at one end thereof to said supporting means, a cylindrical conducting member slidable within said conducting tube, and a wiper within said tube at the end thereof opposite to said one end providing both a frictional coupling and an electrical connection between said tube and said member, said wiper being formed 01' resilient metal and having a polygonal configuration.

6. A high frequency antenna of the dipole type including a pair of adjustable arms and supporting means therefor, each of said arms including an elongated conducting tube secured at one end thereof to said supporting means, a cylindrical conducting member slidable within said conducting tube, and wiper means interposed between said tube and said member and providing both a frictional coupling and an electrical connection therebetween, said wiper means comprising a polygonal resilient sleeve like member, said conducting tube including means for retaining said wiper at the end of said tube opposite to said one end.

7. A high frequency antenna including at least one adjustable arm and supporting means therefor, said arm including an elongated conducting tube secured at one end thereof to said supporting means, a cylindrical conducting member slidable within said conducting tube, and wiper means interposed between said tube and said member and providing both a frictional coupling and an electrical connection therebetween, said wiper means comprising a polygonal resilient 8 sleeve-like member, said conducting tube including means for retaining said wiper at the end of said tube opposite to said one end.

8. Antenna apparatus including in combination, a jack, a base supporting said jack, a plug receivable in said jack, and a high frequency dipole antenna structure supported by said plug, said plug including inner and outer spaced coaxial conductors separated substantially entirely by air so that the capacity therebetween is a minimum, said antenna structure including a stationary insulating portion secured to said plug, a pair of rotatable conducting hub portions disposed on opposite sides of said insulating portion, and a spindle supported by said insulating portion and extending at opposite ends thereof into said hub portions with said hub portions being rotatable about said spindle as an axis, a pair of antenna arms individually supported on said hub portions, means electrically connecting said spindle to one of said hub portions, means insulating said spindle from the other of said hub portions, said spindle being electrically connected to said inner conductor of said plug, and contact means supported on said insulating portion connecting said other hub portion to said outer conductor of said plug.

WILLIAM J. RACE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

